title: In situ quantitative monitoring of polyplexes and polyplex micelles in the blood circulation using intravital real-time confocal laser scanning microscopy.
abstract: Surface modification using poly(ethylene glycol) (PEG) is a widely used strategy to improve the biocompatibility of cationic polymer-based nonviral gene vectors (polyplexes). A novel method based on intravital real-time confocal laser scanning microscopy (IVRTCLSM) was applied to quantify the dynamic states of polyplexes in the bloodstream, thereby demonstrating the efficacy of PEGylation to prevent their agglomeration. Blood flow in the earlobe blood vessels of experimental animals was monitored in a noninvasive manner to directly observe polyplexes in the circulation. Polyplexes formed distinct aggregates immediately after intravenous injection, followed by interaction with platelets. To quantify aggregate formation and platelet interaction, the coefficient of variation and Pearson's correlation coefficient were adopted. In contrast, polyplex micelles prepared through self-assembly of plasmid DNA with PEG-based block catiomers had dense PEG palisades, revealing no formation of aggregates without visible interaction with platelets during circulation. This is the first report of in situ monitoring and quantification of the availability of PEGylation to prevent polyplexes from agglomeration over time in the blood circulation. This shows the high utility of IVRTCLSM in drug and gene delivery research.
authors.affiliation: Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nomoto
authors.forename: Yu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Kanjiro
authors.initials: K
authors.lastname: Miyata
authors.forename: Makoto
authors.initials: M
authors.lastname: Oba
authors.forename: Shigeto
authors.initials: S
authors.lastname: Fukushima
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Yamasoba
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
mesh_terms: D000818:Animals; D001775:Blood Circulation / Q000502:physiology; D001792:Blood Platelets / Q000737:chemistry; D003199:Computer Systems; D054644:Ear Auricle / Q000098:blood supply* / Q000737:chemistry* / Q000187:drug effects; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage / Q000032:analysis*; D007275:Injections, Intravenous; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008823:Micelles; D018613:Microscopy, Confocal / Q000379:methods; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000032:analysis*
chemical_list: D008823:Micelles; D011092:Polyethylene Glycols